Seat angle regulators are used in a vehicle seat for connecting a seat base with a backrest to improve the comfortableness of the seat. Passengers may regulate an angle of the backrest to the best position by the seat angle regulator, thereby obtaining a sitting angle which is the most comfortable and most habitual for passengers. For a driver, it is possible to regulate the angle of the backrest for best view and convenience in controlling the steering wheel, pedals, gear lever or the like.
Currently, an electric seat regulator generally employs the planetary gear transmission principle. Due to the unavoidable manufacturing tolerance of parts, therefore, there is a certain gap inside such angle regulator, such that when used, the gap may cause a lager swing of the seat backrest relative to the fore-and-aft direction of the seat and may accompany noises, thereby influencing the comfortableness of the seat. Therefore, there is often provided a gap eliminating mechanism inside the angle regulator.
A seat angle regulator and a seat with the same are disclosed in Chinese patent application CN.201468560U, the seat angle regulator includes an inner toothed plate with an inner toothed ring, an outer toothed plate with outer toothed ring, an eccentric wheel, a wedge block and a drive cam, wherein the inner toothed plate is used for being fixedly connected with the backrest, a shaft shoulder is provided in the middle of the inner toothed plate; the outer toothed plate is used for being fixedly connected with the seat, a shaft center hole is provided in the middle of the outer toothed plate; the outer toothed ring is engaged with the inner toothed ring and there is a radial eccentric area formed between the shaft shoulder and the shaft center hole; the eccentric wheel is disposed in the radial eccentric area, the eccentric wheel, the inner toothed plate and the outer toothed plate constitute a planetary gear transmission mechanism with small teeth number difference; the wedge block is disposed in the radial eccentric area; furthermore, under the action of a circumferential force applied by an elastic member, the eccentric wheel and the wedge block eliminate the gaps between the eccentric wheel and an shaft center hole of the inner toothed plate and between the engaged teeth; the drive cam drives the eccentric wheel or the wedge block, to achieve an angle rotation of the inner toothed plate relative to the outer toothed plate; the eccentric wheel is in an integrated eccentric ring shape, and fully fills a forward eccentric area formed between the shaft of the inner toothed plate and the shaft center hole of the outer toothed plate; the wedge block is disposed in a recess of the eccentric wheel.
In the above-mentioned solution, for the purpose that the wedge block is pressed tightly circumferentially by the elastic member to eliminate the gaps inside the angle regulator and in order to be adapted to the assembling and manufacturing tolerance, the wedge block needs to have an enough circumferential placement space to ensure that the wedge block can be always in a wedged state. Therefore, it is necessary to provide a void operation stoke between the drive cam and the wedge block, as a space indicated by the angles a and b in FIG. 1. In a regulation process of the angle regulator, particularly in a reversing regulation process of the backrest, when the drive cam drives the wedge block by driving the eccentric wheel to reverse, the drive cam needs firstly to pass the preset void operation stoke, i.e., the sum of the angles a and b, and then drives the wedge block to rotate, thereby realizing the reversing regulation of angle of the backrest. Since the drive cam needs to pass a certain void operation stoke, in the seat backrest reversing regulation process, users may feel a relatively obvious delay of the backrest regulation action, there is a certain waiting time, thereby influencing the comfortableness of the use of the seat.
Further, in the backrest reversing process, under the driving of an electric motor, the drive cam firstly rotates to pass the void operation stoke and then contacts with the wedge block/the eccentric wheel to realize the angle regulation. In this process, because the electric motor has no load, the drive cam hits the static wedge block/the eccentric wheel at a relatively high speed, therefore, in the backrest reversing process, relatively obvious noises will be generated, and also the comfortableness of the seat will be influenced.
Against the above two failure modes, there is disclosed a seat with an adjustable backrest incline angle and particularly an adjusting assembly of vehicle seats in Chinese patent document CN1149157C. In this document there is provided a new solution for improving the comfortableness of a seat, in which a synchronous ring is used to drive two wedges which are pressed tightly toward both sides under the action of an elastic element to eliminate a gap, as shown in FIG. 2. Though this solution may reduce the void operation stoke and weaken noises, after repeated tests, the inventor finds the further drawbacks: since one of the wedges is driven under a friction force of the synchronous ring in the backrest regulation process and this wedge cannot timely and effectively provide a gap required for a motion, an operation torque of the angle regulator would inevitably increase and a fluctuation of the torque value would increase, thereby a burden of an electric motor would increase such that the problems of an increasing noise, easy to overload, a decreased life and the like would occur when the electric motor operates, and for the angle regulator itself, wear and tear of parts would be speeded up, and a trend of increase in the backrest gap would be obvious after the angle regulator is used for a period of time, thereby influencing the stability in the backrest regulation process and the comfortableness in use.